Support Forces

QUESTION TWO: AT THE AIRPORT
Some painters are working at the airport. They have a uniform plank resting on two supports. The plank is 4.0 m long. It has a mass of 22 kg. The two legs that support the plank are 0.50 m from either end.

(a)The plank is in equilibrium. Draw labelled arrows of appropriate sizes in the correct position showing the forces acting on the plank on the diagram above.

(b)Calculate the support force on the plank at A if a painter of mass 60 kg sits 0.75 m from A, and another painter of mass 75 kg sits at a distance of 0.80 m from B.
Use g = 10 m s–2.

2. Relevant equations
Torque = Force x Distance

3. The attempt at a solution
I was away when my class covered support forces, so I haven't got the faintest clue how to do it. I'm not so much looking for an answer, because this is not homework, I'm looking for an explanation which I can use to answer this question later in the year

Just saying that you were not in the class isn't gonna cut it. Support forces aren't a topic that you should be taught as such. It can be deduced from what you've been doing in prior classes. Consult your textbook for Rotational and Translational equilibrium, two dimensional mechanics and try to think of a way to do this problem. We cannot help you with no efforts from your side. The forum guidelines clearly state that.